There's probably only one thing more terrifying than Nazi soldiers: Nazi soldiers with jet packs—and Nazi UFOs piloted by nefarious hamsters. The difference is that, while the UFOs never existed, the Nazi jet pack did: Behold, the Himmelstürmer.
The Himmelstürmer—or Skystormer—used a pulse jet engine, like the one that powered the Fieseler Fi 103 flying bomb. The Fi 103 was the official name of the the infamous V-1 Buzz Bomb, which terrorized England for a while, until the RAF pilots learnt to shoot it down over the Channel... and the Nazis introduced the V-2 ballistic missile, invented by Saturn V rocket scientist Wernher von Braun.
The Himmelstürmer was designed for one purpose: To make Nazi soldiers in their engineering corps to jump over enemy defenses, like minefields, barbed wire, or trenches, as well as rivers, or any other large natural obstacle. It had two components. The main pulse engine—on the back—pushed up and forward. A second pulse engine on the front pushed only up.
The engineer throttled the back engine to make him jump over greater or shorter distances. It consumed very little fuel, never ran hot, and didn't require special clothing because it wasn't designed to run for long period of times. All while achieving 180 feet jumps at an altitude of 50 feet. Impressive. Fortunately, like all their secret super-weapons, it arrived late in the war.
While no photos of the Himmelstürmer remain—the image above is a recreation—Bell Aerosystems got the devices at the end of the war, but changed its design thinking they could turn every soldier into Superman, instead of just super-jumpers. Their version, however, wasn't reliable enough for real action, and was canned after a few years. [DRB and Wikipedia]